One of the simplest characteristics of dinosaurs that paleontologists still know little about is how they slept.
New studies have shown that when some smaller dinosaurs slept, they curled up much like birds do today. Though most dinosaur fossils are found in the dinosaur “death pose,” some dinosaurs (who have died while they were sleeping) have been found in a roosting position, similar to the sleeping position of most modern birds.
Researchers are now discovering that giant plant-eaters, such as Hadrosaurids or a Corythosaurus, may have had teeth with grinding surfaces much like a modern day horse or bison. Their teeth were complex, combining up to six types of tissue, and all varying in hardness. Scientists speculate that this is due to their diets, including tough, tooth-gouging particles from plants.
Researchers believe the complex nature of the herbivores teeth is reason that they were so common.
Two Sinocalliopteryx gigas, which are carnivorous dinosaurs about 6 feet long and covered in hair-like fuzz, were discovered in Liaoning, China with evidence of their last meals remaining in their stomachs.
One of the paleontologists working with the specimens stated that stomach remains are “…extremely rare in the fossil record”, so this discovery gives scientists evidence of interaction between dinosaurs. Though it is still unknown whether or not these dinosaurs hunted or scavenged the prey found in their stomachs, it gives scientists a look into their diets.
A dinosaur foot print was found in the backyard of NASA’s Goddard Space Flight Center campus in Maryland, measuring in at 12-inches wide. The footprint is believed to belong to a Nodosaur, a plant-eating, armor studded dino that roamed the area about 110 million years ago.
Several other smaller dinosaur footprints were also discovered in the backyard of NASA, most likely from theropods.
Several remains of primitive shark’s teeth, with at least three of the teeth dating back from 270 million years ago, were discovered in what is known as the Kaibab Formation of northern Arizona. It is believed that the three sharks range from about 3 feet to 20 feet long, and that Arizona was home to a very diverse shark population in the Cretaceous period.
About 75 million years ago, duck-billed and horned dinosaurs flourished in Canada, while only a few of these species emerged in the United States.
Scientists believe that this diversity among dinosaurs caused a dinosaur boom when the Rocky Mountains were formed, creating geographic and ecological barriers between species. This not only rapidly increased the population of certain dinosaur species, but it in turn reduced the pace at which new species evolved.
Dinosaurs may not have been cold-blooded species. Scientists previously believed animals were ectothermic when their bones exhibited growth lines, but recent studies have found growth lines in bones of mammals, specifically those that lived through long periods of unfavorable environmental conditions, like rainfall and temperature changes.
Researchers in South Africa have discovered the oldest known dinosaur nesting site to date, dating to 190 million years ago. The findings include multiple nests, eggs, and hatchlings belonging to the Massospondylus, an herbivorous dinosaur with a small head and long neck. 10 nests have been found so far, and scientists predict there are many more to be unearthed.
Read more about the discovery and the condition of the nests and eggs on the Huffington Post.